One of the most common techniques used in complex law enforcement investigations that potentially involve many players, it’s a common practice for prosecutors and investigators to focus on lower level officials and associates in the hope that they can get them to become cooperating witnesses, or as it’s generally called in law enforcement, “flipping” a witness. Typically, this involves gathering evidence against one of these lower-level targets and either indicting them or threatening to do so unless they agree to plead guilty in exchange for information about targets further up the food chain. It’s a tactic that’s been used in the past in everything from Mafia prosecutions to investigations of suspected conspiracies involving white collar crimes in private industry and in government. Now, based on two separate reports out today, it appears to be happening in the ongoing investigation by special counsel Robert Mueller’s investigation of Russian interference in the Presidential campaign and possible contacts between officials close to President Trump and Russian officials, and the target of choice seems to be former lobbyist and Trump campaign manager Paul Manafort.

First up, there’s a report from The New York Times detailing the extent of Mueller’s efforts to pin charges down against Manafort;

WASHINGTON — Paul J. Manafort was in bed early one morning in July when federal agents bearing a search warrant picked the lock on his front door and raided his Virginia home. They took binders stuffed with documents and copied his computer files, looking for evidence that Mr. Manafort, President Trump’s former campaign chairman, set up secret offshore bank accounts. They even photographed the expensive suits in his closet.

The special counsel, Robert S. Mueller III, then followed the house search with a warning: His prosecutors told Mr. Manafort they planned to indict him, said two people close to the investigation.

The moves against Mr. Manafort are just a glimpse of the aggressive tactics used by Mr. Mueller and his team of prosecutors in the four months since taking over the Justice Department’s investigation into Russia’s attempts to disrupt last year’s election, according to lawyers, witnesses and American officials who have described the approach. Dispensing with the plodding pace typical of many white-collar investigations, Mr. Mueller’s team has used what some describe as shock-and-awe tactics to intimidate witnesses and potential targets of the inquiry.

Mr. Mueller has obtained a flurry of subpoenas to compel witnesses to testify before a grand jury, lawyers and witnesses say, sometimes before his prosecutors have taken the customary first step of interviewing them. One witness was called before the grand jury less than a month after his name surfaced in news accounts. The special counsel even took the unusual step of obtaining a subpoena for one of Mr. Manafort’s former lawyers, claiming an exception to the rule that shields attorney-client discussions from scrutiny.

“They are setting a tone. It’s important early on to strike terror in the hearts of people in Washington, or else you will be rolled,” said Solomon L. Wisenberg, who was deputy independent counsel in the investigation that led to the impeachment trial of President Bill Clinton in 1999. “You want people saying to themselves, ‘Man, I had better tell these guys the truth.’”

A spokesman for Mr. Mueller declined to comment. Lawyers and a spokesman for Mr. Manafort also declined to comment.

Few people can upend Washington like a federal prosecutor rooting around a presidential administration, and Mr. Mueller, a former F.B.I. director, is known to dislike meandering investigations that languish for years. At the same time, he appears to be taking a broad view of his mandate: examining not just the Russian disruption campaign and whether any of Mr. Trump’s associates assisted in the effort, but also any financial entanglements with Russians going back several years. He is also investigating whether Mr. Trump tried to obstruct justice when he fired James B. Comey, the F.B.I. director.

Mr. Manafort is under investigation for possible violations of tax laws, money-laundering prohibitions and requirements to disclose foreign lobbying. Michael T. Flynn, the former national security adviser, is being scrutinized for foreign lobbying work as well as for conversations he had last year with Russia’s ambassador to the United States. On Monday, Mr. Flynn’s siblings announced the creation of a legal-defense fund to help cover their brother’s “enormous” legal fees.

The Times report goes on to note that, at least for now, the Mueller investigation has treated the White House and other officials close to Trump, such as Trump’s son-in-law far differently from the way it is proceeding against people such as Manafort and former National Security Adviser retired Lt. General Michael Flynn. In the former case, Mueller’s team of attorneys and lawyers are working closely with attorneys representing the White House, Trump personally, and the people close to him, on issues such as the production of documents for the purpose of aiding in the investigation and related issues. With respect to the later, Mueller’s team is acting in a more confrontational mode, such as obtaining a typically hard to get “no-knock” warrant against Manafot that essentially meant that Federal agents obtained court permission to pick the locks to Manafort’s home in the early morning while he slept and wake him up with agents and investigators already in his home ready to begin their search. In order to obtain such a warrant, investigators would have generally been required to demonstrate to a judge that if they attempted to serve a warrant in the normal fashion there was probable cause to believe that Manafort would attempt to destroy records or delete computer files that may contain incriminating evidence. The Mueller team has treated Flynn in a similar manner, although it’s not clear he’s being subjected to quite the same kind of treatment that has been focused on Manafort.

In addition to the Times report, CNN reports that Federal law enforcement had secured warrants to wiretap Manafort’s communications with foreign officials long before he was a member of the Trump inner circle:

US investigators wiretapped former Trump campaign chairman Paul Manafort under secret court orders before and after the election, sources tell CNN, an extraordinary step involving a high-ranking campaign official now at the center of the Russia meddling probe.

The government snooping continued into early this year, including a period when Manafort was known to talk to President Donald Trump.

Some of the intelligence collected includes communications that sparked concerns among investigators that Manafort had encouraged the Russians to help with the campaign, according to three sources familiar with the investigation. Two of these sources, however, cautioned that the evidence is not conclusive.

Special counsel Robert Mueller’s team, which is leading the investigation into Russia’s involvement in the election, has been provided details of these communications.

A secret order authorized by the court that handles the Foreign Intelligence Surveillance Act (FISA) began after Manafort became the subject of an FBI investigation that began in 2014. It centered on work done by a group of Washington consulting firms for Ukraine’s former ruling party, the sources told CNN.

The surveillance was discontinued at some point last year for lack of evidence, according to one of the sources.

The FBI then restarted the surveillance after obtaining a new FISA warrant that extended at least into early this year.

Sources say the second warrant was part of the FBI’s efforts to investigate ties between Trump campaign associates and suspected Russian operatives. Such warrants require the approval of top Justice Department and FBI officials, and the FBI must provide the court with information showing suspicion that the subject of the warrant may be acting as an agent of a foreign power.

It is unclear when the new warrant started. The FBI interest deepened last fall because of intercepted communications between Manafort and suspected Russian operatives, and among the Russians themselves, that reignited their interest in Manafort, the sources told CNN. As part of the FISA warrant, CNN has learned that earlier this year, the FBI conducted a search of a storage facility belonging to Manafort. It’s not known what they found.

The conversations between Manafort and Trump continued after the President took office, long after the FBI investigation into Manafort was publicly known, the sources told CNN. They went on until lawyers for the President and Manafort insisted that they stop, according to the sources.

It’s unclear whether Trump himself was picked up on the surveillance.

The White House declined to comment for this story. A spokesperson for Manafort didn’t comment for this story.

As the CNN report goes on to note, the investigation into Manafort goes back several years and began as early as 2014 as part of the Justice Department’s investigation of Viktor Yanukovych, the former pro-Russian President of Ukraine who was overthrown in 2014 in the wake of nationwide protests and whose departure from the country was in many ways the origin of the ongoing conflict between Ukraine and Russia. Yanukovych was suspected of embezzling billions of dollars from the Ukrainian government and hiding in personal accounts overseas and Manafort and his firm came to be a focus of the investigation due to the fact that it had conducted lobbying work for the Yanukovych regime in the United States. While that investigation ended a year or more ago when it was concluded there was no connection between Manafort and anything Yanukovych may have done, he quickly came back into focus in the new investigation of Russian interference in the election and questions about the Trump campaign’s ties to Russia. As a result, new warrants were issued and Manafort came back under surveillance again. What this subsequent investigation, and the renewed wiretaps, may have uncovered is as yet unclear but the fact that they lasted for a considerable period of time could be an indication that they were picking up conversations that investigators considered relevant to the investigation.

Obviously, it’s far too early to say what if anything may come of all this. It may turn out that the effort to flip potential targets like Manafort and Flynn will prove to be unfruitful, or that they don’t possess any information regarding Russian interference or ties between Trump or any of the members of his inner circle. In that case, the likelihood of a generous plea deal in exchange for their cooperation would be fairly low. If it turns out that both or either one of them has inforation about others that could be of use to investigators, that could prove to be a serious problem for Trump, his Administration, and people in his inner circle such as Jared Kushner. Whatever the case may be, it’s clear that Mueller is a man on a mission and he’s not going to stop until he’s uncovered every stone his investigation may stumble upon.